diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fb800f0..e7a25fe 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java: [11, 17]
+        java: [11, 17, 21]
     steps:
       - uses: actions/checkout@v2